1. Field of the Invention
The present invention relates to a resistor apparatus, and especially relates to a terminal resistor apparatus.
2. Description of Prior Art
RS485 is a conventional communication standard for industrial environment. Controller area network (CAN or CAN-bus) is a conventional communication standard for vehicles. When the RS485 or the controller area network is used, the first of the electronic apparatus in the network will need to be connected to a terminal resistor to decrease signal interference, and the last of the electronic apparatus in the network will also need to be connected to a terminal resistor to decrease signal interference.
FIG. 1 shows a block diagram of the network connection of the RS485 (or controller area network) of prior art. An electronic apparatus 102 includes a communication integrated circuit 104. The communication integrated circuit 104 includes a high electric potential side 106 and a low electric potential side 108 to communicate with other electronic apparatus 102. These high electric potential sides 106 are electrically connected. These low electric potential sides 108 are electrically connected. The first of the electronic apparatus 102 will need to be connected to a terminal resistor 110 to decrease signal interference, and the last of the electronic apparatus 102 will also need to be connected to a terminal resistor 110 to decrease signal interference.
In the prior art, the users install the terminal resistors 110 manually in the first of the electronic apparatus 102 and in the last of the electronic apparatus 102 after the users find out the first of the electronic apparatus 102 and the last of the electronic apparatus 102. It is very inconvenient and easy to make mistakes.